Solar panels

Solar energy has move on dramatically over the last 10 Years it is now a viable source of most if not all the energy for your home.

Here is a table showing electricity output for a PV system in the South of England.

A south facing 4kW PV system based in the Berkshire area will, on average, generate the following electricity:

Types of Solar energy systems

There are two main types of solar panel, one type heats water and the other type produces electricity. Both types of solar panels are increasingly popular for domestic, industrial and commercial applications.

Solar water heating panels are also called 'solar thermal' panels or 'solar absorber' panels. This type of solar panel uses direct & indirect energy from the sun to heat water in a very simple and efficient process.

Photovoltaic solar panels produce electricity and are often referred to as solar 'PV panels’ or ‘solar modules'. This type of solar panel has no moving parts and produces current when exposed to high levels of light.

Photovoltaic panels (PV)

Photovoltaic solar panels generate power when exposed to high levels of light. The photovoltaic effect was discovered in 1839 by nineteen-year-old Edmund Becquerel. Modern PV modules were first developed commercially for NASA at the time of the space race in the 1950's. With no moving parts, solar PV is a silent and reliable method of producing

electricity. High quality solar modules have power performance warranties of 20 years on the larger panels, with an expected life of 60 years or more. One early commercial PV system, now 46 years old, is still producing power within those warranty guidelines.

Solar PV panels are currently available in three main silicon-based technologies. Monocrystalline cells are the most efficient and also the most expensive. Polycrystalline cells are almost as efficient as mono and less expensive to manufacture. Amorphous PV modules are the most cost effective and they perform better than the other types in cloudy conditions, however for the same power output they require more installation space and tend to be impractical for most UK dwellings. Also see our section on PV shading.

Solar Thermal panels

These are collectors that convert the energy from the sun into heat which is transferred by a liquid into your hot water heating system. You will need to have a twin coiled hot water cylinder for this type of renewable.

Absorbers are usually black, or dark as these surfaces demonstrate a particularly high degree of light absorption. The level of absorption is the amount of useful short-wave solar radiation being absorbed and not reflected.

As the absorber warms up to a temperature higher than the ambient temperature, it gives off a great part of the accumulated solar energy in form of useful heat which can be used to heat a domestic hot water cylinder.

In order to reduce energy loss through heat emission, the most efficient absorbers have a selective surface coating. This coating enables the conversion of a high proportion of the solar radiation into heat, simultaneously reducing the emission of heat. The usual coatings provide a degree of absorption of over 90%.

PV and absorption panels

Quite simply a combination of the two above, the PV panels are cooled by the water running through the absorption layer and the heat

that is taken away is then be used to heat water. PVT systems can generate up to 20% more electricity due to the cooling effect of the water passing through them and in addition may qualify for the renewable Heat Incentive from October 2012.

PV Shading

This is an issue that has affected all type of Solar panels but has not really been properly addressed. It is being taken much more seriously now. Please visit our section on PV Shading section where it is fully explained.